$($a$)$

Write the expression for y as a function of x and t in SI units for a sinusoidal wave traveling along a rope in the negative x direction with the following characteristics: A $=8\mathrm{.}75$ cm$,=70\mathrm{.}0$ cm$,$ f $=4\mathrm{.}00$ Hz$,$ and y$(0,$ t$)=0$ at t $=0.($Use the following as necessary: x and t$.)$

y $=$

$($b$)$

Write the expression for y as a function of x and t for the wave in part $($a$)$ assuming y$($x$,0)=0$ at the point x $=28\mathrm{.}5$ cm$.($Use the following as necessary: x and t$.)$

y $=$